Corpus: Hepatic Portal vein

The vena portae, or portal vein, is the portal vessel that transports oxygen-poor, nutrient-rich blood into the liver.

The portal veins of the pituitary gland are discussed under Venae portales hypophysiales.

The portal vein is located dorsal to the pancreas and runs there together with the hepatic propria artery in the hepatoduodenal ligament to the hepatic portal (porta hepatis). It enters the liver via this portal.

After the vein enters the hepatic portal, it divides into two branches to the right and left lobes of the liver. It then branches out into further small vascular branches that finally end in the hepatic sinusoids.

The portal vein arises from the union of the superior mesenteric vein with the splenic vein (lienal vein), which is known as the confluence. The portal vein also receives blood from the inferior mesenteric vein via the lienal vein. Other venous tributaries of the portal vein are:

• Vena gastrica dextra (from the stomach)
• Vena gastrica sinistra (from the stomach)
• Vena pylorica (from the pylorus)
• Vena pancreaticoduodenalis superior posterior (from the pancreas)

Smaller branches are the cystic vein (gallbladder) and the paraumbilical veins.

The nutrient-rich blood absorbed from the gastrointestinal tract is first collected via the portal vein and channelled into the liver before it enters the large circulation. This bypass circulation is known as the portal vein circulation. This ensures the processing of nutrients and the rapid and effective elimination of toxins (e.g. ammonia).

The most important pathological changes in the portal vein include

• Portal vein thrombosis
• Portal hypertension